1. Field of the Invention
The present invention relates to a ceramic composition and a method for manufacturing the same, and more particularly to a ceramic composition for absorbing electromagnetic wave generated from electric devices such as a cellular phone, a beeper, a computer, a cordless telephone etc., and a method for manufacturing the same.
2. Description of the Prior Art
Generally, fine ceramics or new ceramics are different from conventional ceramics in their composition and their manufacturing method such as forming and sintering. That is, fine ceramics are manufactured by a forming method and a sintering method which exactly control a precisely prepared composition by using an artificial raw powder or a highly purified raw powder. Thus, fine ceramics have a greater number of applications than conventional ceramics. Fine ceramics are used for various purposes because various applications of fine ceramics have recently been discovered.
Fine ceramics are generally classified into oxide type ceramics and non-oxide type ceramics. An oxide type ceramic includes alumina (Al.sub.2 O.sub.3), ferrite (Fe.sub.2 O.sub.3), zirconia (ZrO.sub.2), and titania (TiO.sub.2) etc. A non-oxide type ceramic includes silicon carbide (SiC), and silicon nitride (Si.sub.3 N.sub.4) and so on. At present, new applications for fine ceramics such as thermal applications, mechanical applications, bio-chemical applications, electric applications, electronic applications, and optic applications are being discovered, and the research concerning these applications will be continued.
At present, many electric devices such as cellular phones, beepers, computers, cordless telephones, televisions etc., are utilized during daily life. It is necessary to use these electric devices in modern daily life, but most of these devices radiate electromagnetic waves. It is well known to everybody that the electromagnetic waves generated from these electric devices are harmful to people who use these electric devices. Therefore, it is continued that the research for shielding the harmful electromagnetic waves generated from these electric devices. Such pellets for making electromagnetic wave shielding material are disclosed in U.S. Pat. No. 4,960,642 (issued to Izumi Kosuga et. al). The pellets can shield electromagnetic wave by inserting conductive fibers into a matrix resin. Also, it is disclosed that a method for absorbing electromagnetic waves generated from electric devices by means of installing a ferrite core into these electric devices.
However, above-described pellets and method can't block enough of the electromagnetic waves generated from these electric devices, and the manufacturing method and the structure of these devices are complicated because the pellets and the magnetic core are inserted on the circuit board of the electromagnetic devices.